1. Field of the Invention
In general, this invention relates to multilayer graphic articles and, more particularly, to multilayer graphic articles which comprise a substrate, a color layer disposed on the substrate, and an overlying protective surface layer.
2. Description of Related Art
Multilayer graphic articles may be applied to a variety of surfaces for decorative, informational, and/or functional reasons. These multilayer constructions often contain one or more continuous or non-continuous color layers coated, printed or laminated on a plastic film, which itself may be colored.
Decorative graphic articles are typically highly contrasting polychromatic constructions that enhance the visual appeal of surfaces to which they are applied, such as motor vehicles, marine craft, commercial or residential real estate, signs, store displays and the like. Informational graphic articles provide directions, location indicia, instructions, and identification when used, for example, to construct road signs and license plates. Functional graphic articles impart weather protection and wear resistance to surfaces to which they are applied, especially outdoor surfaces.
Color layers in presently known graphic articles often contain a poly(vinyl chloride) (PVC) binder blended with various color agents, volatile solvents and plasticizers. PVC solvents typically provide from 40 to 60 weight percent (wt. %) of the color layer formulation. However, for various environmental and health reasons, it is desirable to reduce or eliminate the use of these solvents. Similarly, it is desirable to reduce or eliminate the use of PVC plasticizers. Plasticizers can migrate into adjacent layers of the graphic and cause visual changes to both the color layer and surrounding surfaces. The physical stability of the color layer may be adversely affected. Finally, PVC plasticizers are not considered environmentally friendly.
Presently known color layer formulations are compatible with only a limited class of substrates, primarily PVC, acrylics and urethanes. These substrates can have poor flexibility and PVC is not environmentally desirable.
Accordingly, a substantial need exists for eliminating or reducing the use of PVC-based materials (and their associated solvents and plasticizers) in both color layer formulations and graphic articles.